Melittin induces human gastric cancer cell apoptosis via activation of mitochondrial pathway

AIM: To investigate the apoptotic effects of melittin on SGC-7901 cells via activation of the mitochondrial signaling pathway in vitro.METHODS: SGC-7901 cells were stimulated by melittin, and its effect on proliferation and apoptosis of was investigated by methyl thiazolyl tetrazolium assay, morphologic structure with transmission electron microscopy, annexin-V/propidium iodide double-staining assay, measuring mitochondrial membrane potential(MMP) levels, and analyzing reactive oxygen species(ROS) concentrations were analyzed by flow cytometry. Cytochrome C(Cyt C), apoptosis-inducing factor(AIF), endonuclease G(Endo G), second mitochondria-derived activator of caspases(Smac)/direct IAP binding protein with low isoelectric point(Diablo), and FAS were analyzed by western blot. The expression of caspase-3 and caspase-8 was measured using activity assay kits.RESULTS: Melittin was incubated at 1.0, 2.0, 4.0, or 6.0 μg/m L for 1, 2, 4, 6, or 8 h and showed a timeand concentration-dependent inhibition of SGC-7901 cell growth. Melittin induced SGC-7901 cell apoptosis, which was confirmed by typical morphological changes. Treatment with 4 μg/m L melittin induced early apoptosis of SGC-7901 cells, and the early apoptosis rates were 39.97% ± 3.19%, 59.27% ± 3.94%, and 71.50% ± 2.87% vs 32.63% ± 2.75% for 1, 2, and 4 h vs 0 h(n = 3, P 0.05); the ROS levels were 616.53% ± 79.78%, 974.81% ± 102.40%, and 1330.94% ± 93.09% vs 603.74% ± 71.99%(n = 3, P 0.05); the MMP values were 2.07 ± 0.05, 1.78 ± 0.29, and 1.16 ± 0.25 vs 2.55 ± 0.42(n = 3, P 0.05); caspase-3 activity was significantly higher compared to the control(5492.3 ± 321.1, 6562.0 ± 381.3, and 8695.7 ± 449.1 vs 2330.0 ± 121.9), but the caspase activity of the non-tumor cell line L-O2 was not different from that of the control. With the addition of the caspase-3 inhibitor(Ac-DEVD-CHO), caspase-3 activity was significantly decreased compared to the control group(1067.0 ± 132.5 U/g vs 8695.7 ± 449.1 U/g). The expression of the Cyt C, Endo G, and AIF proteins in SGC-7901 cells was significantly higher than those in the control(P 0.05), while the expression of the Smac/Diablo protein was significantly lower than the control group after melittin exposure(P 0.01). Ac-DEVD-CHO did not, however, have any effect on the expression of caspase-8 and FAS in the SGC-7901 cells.CONCLUSION: Melittin can induce apoptosis of human gastric cancer(GC) cells through the mitochondria pathways, and it may be a potent agent in the treatment of human GC.     

High dose glargine alters the expression profiles of microRNAs in pancreatic cancer cells

AIM: To investigate the effect of high dose glargine on the expression profiles of microRNAs in human pancreatic cancer cells.METHODS: Real-time polymerase chain reaction array (RT-PCR) was applied to investigate miRNAs differentially expressed in Sw1990 cells treated with or without 100 IU/L glargine. Stem-loop RT-PCR was used to confirm the results of the array assay in Sw1990 and Panc-1 cells. The effects of miR-95 on cell growth, apoptosis, invasion and migration abilities were respectively examined by CCK8 assay, apoptosis assay, Matrigel invasion and migration assay in Sw1990 and Panc-1 cells. Nude mice xenograft models with Sw1990 cells were built to investigate pancreatic cancer growth in vivo after transfection by the lentivirus pGLV3-GFP- miR-95.RESULTS: Ten miRNAs were significantly up-regulated and 2 miRNAs down-regulated in glargine treated Sw1990 cells when compared with non-treated cells (2.48-fold changes on average, P < 0.01). miR-95, miR-134 and miR-34c-3p are the top three miRNAs regulated by glargine (3.65-fold, 2.67-fold and 2.60-fold changes respectively, P < 0.01) in Sw1990 cells. Stem-loop RT-PCR confirmed that high dose glargine up-regulated the expression of miR-95 and miR-134 in both Sw1990 and Panc-1 cells. The most obvious change is the apparent increase of miR-95. Forced expression of miR-95 significantly increased cell proliferation (Sw1990: 2.510 ± 0.129 vs 2.305 ± 0.187, P < 0.05; Panc-1: 2.439 ± 0.211 vs 2.264 ± 0.117, P < 0.05), invasion (Sw1990: 67.90 ± 12.33 vs 47.30 ± 5.89, P < 0.01; Panc-1: 37.80 ± 8.93 vs 30.20 ± 5.14, P < 0.01), migration (Sw1990: 101 ± 6.00 vs 51.20 ± 8.34, P < 0.01; Panc-1: 91.80 ± 9.22 vs 81.50 ± 7.47, P < 0.01) and inhibited cell apoptosis (Sw1990: 22.05% ± 1.92% vs 40.32% ± 1.93%, P < 0.05; Panc-1: 20.17% ± 0.85% vs 45.60% ± 1.43%, P < 0.05) when compared with paired negative controls, whereas knockdown of miR-95 obtained the opposite effect. Nude mice xenograft models confirmed that miR-95 promoted the growth of pancreatic cancer in vivo when compared with negative control (tumor volume: 373.82 ± 23.67 mL vs 219.69 ± 17.82 mL, P < 0.05).CONCLUSION: These observations suggested that modulation of miRNA expression may be an important mechanism underlying the biological effects of glargine.     

Axl glycosylation mediates tumor cell proliferation, invasion and lymphatic metastasis in murine hepatocellular carcinoma

AIM: To investigate the effects of Axl deglycosylation on tumor lymphatic metastases in mouse hepatocellular carcinoma cell lines. METHODS: Western blotting was used to analyze the expression profile of Axl glycoprotein in mouse hepa-tocellular carcinoma cell line Hca-F treated with tunicamycin and PNGase F 3-(4,5)-dimethylthiazol(-zyl)-3,5- diphenyltetrazolium bromide (MTT) assay, extracellular matrix (ECM) invasion assay (in vitro ) and tumor metastasis assay (in vivo ) were utilized to evaluate the effect of Axl deglycosylation on the Hca-F cell proliferation, invasion and lymphatic metastasis. RESULTS: Tunicamycin and PNGase F treatment markedly inhibited Axl glycoprotein synthesis and expression, proliferation, invasion, and lymphatic metastasis both in vitro and in vivo . In the MTT assay, proliferation was apparent in untreated Hca-F cells compared with treated Hca-F cells. In the ECM invasion assay (in vitro ), treated cells passed through the ECMatrix gel in significantly smaller numbers than untreated cells (tunicamycin 5 μg/mL: 68 ± 8 vs 80 ± 9, P=0.0222; 10 μg/mL: 50 ± 6vs 80 ± 9,P=0.0003; 20 μg/mL: 41 ± 4 vs 80 ± 9, P=0.0001); (PNGase F 8 h: 66 ± 7 vs 82 ± 8, P=0.0098; 16 h: 49 ± 4 vs 82 ± 8, P=0.0001; 24 h: 34 ± 3 vs 82 ± 8, P=0.0001). In the tumor metastasis assay (in vivo ), average lymph node weights of the untreated Hca-F group compared with treated Hca-F groups (tunicamycin 5 μg/mL: 0.84 ± 0.21 g vs 0.72 ± 0.19 g, P=0.3237; 10 μg/mL: 0.84 ± 0.21 g vs 0.54 ± 0.11 g, P=0.0113; 20 μg/mL: 0.84 ± 0.21 g vs 0.42 ± 0.06 g, P=0.0008); (PNGase F 8 h: 0.79 ± 0.15 g vs 0.63 ± 0.13 g, P=0.0766; 16 h: 0.79 ± 0.15 g vs 0.49 ± 0.10 g, P=0.0022; 24 h: 0.79 ± 0.15 g vs 0.39 ± 0.05 g, P=0.0001). Also, average lymph node volumes of the untreated Hca-F group compared with treated Hca-F groups (tunicamycin 5 μg/mL: 815 ± 61 mm 3 vs 680 ± 59 mm 3 , P=0.0613; 10 μg/mL: 815 ± 61 mm 3 vs 580 ± 29 mm 3 , P=0.0001; 20 μg/mL: 815 ± 61 mm 3 vs 395 ± 12 mm 3 , P=0.0001); (PNGase F 8 h: 670 ± 56 mm 3 vs 581 ± 48 mm 3 , P=0.0532; 16 h: 670 ± 56 mm 3 vs 412 ± 22 mm 3 , P=0.0001; 24 h: 670 ± 56 mm 3 vs 323 ± 11 mm 3 , P=0.0001). CONCLUSION: Alteration of Axl glycosylation can at-tenuate neoplastic lymphatic metastasis. Axl N-glycans may be a universal target for chemotherapy.     

Tumor suppressor function of ezrin-radixin-moesin-binding phosphoprotein-50 through β-catenin/E-cadher in pathway in human hepatocellular cancer

AIM:To determine the effect and molecular mechanism of ezrin-radixin-moesin-binding phosphoprotein-50(EBP50) in hepatocellular carcinoma(HCC).METHODS:Three human HCC cell lines,i.e.,SMMC7721,HepG2 and Hep3B,were used.We transfected the Pbk-CMV-HA-EBP50 plasmid into SMMC7721 cells with Lipofectamine 2000 to overexpress EBP50.Western blotting were performed to determine the effects of the plasmid on EBP50 expression and to detect the expression of β-catenin and E-cadherin before and after the transfection of the plasmid into SMMC7721 cells.In vitro cell proliferation was assessed with a Cell Counting Kit-8(CCK-8) assay.Cell cycle distribution was assessed with flow cytometry.Invasion and migration ability of before and after the transfection were determined with a transwell assay.Cell apoptosis was demonstrated with Annexin V-FITC.The effect of EBP50 overexpressing on tumor growth in vivo was performed with a xenograft tumor model in nude mice.RESULTS:The transfection efficiency was confirmed with Western blotting(1.36 ± 0.07 vs 0.81 ± 0.09,P < 0.01).The CCK8 assay demonstrated that the growth of cells overexpressing EBP50 was significantly lower than control cells(P < 0.01).Cell cycle distribution showed there was a G0/G1 cell cycle arrest in cells overexpressing EBP50(61.3% ± 3.1% vs 54.0% ± 2.4%,P < 0.05).The transwell assay showed that cell invasion and migration were significantly inhibited in cells overexpressing EBP50 compared with control cells(5.8 ± 0.8 vs 21.6 ± 1.3,P < 0.01).Annexin V-FITC revealed that apoptosis was significantly increased in cells overexpressing EBP50 compared with control cells(14.8% ± 2.7% vs 3.4% ± 1.3%,P < 0.05).The expression of β-catenin was downregulated and E-cadherin was upregulated in cells overexpressing EBP50 compared with control cells(0.28 ± 0.07 vs 0.56 ± 0.12,P < 0.05;0.55 ± 0.08 vs 0.39 ± 0.07,P < 0.05).In vivo tumor growth assay confirmed that up-regulation of EBP50 could obviously slow the growth of HCC derived from SMMC7721 cells(     

Function of chloride intracellular channel 1 in gastric cancer cells

AIM: To investigate the effect of chloride intracellular channel 1 (CLIC1) on the cell proliferation, apoptosis, migration and invasion of gastric cancer cells.METHODS: CLIC1 expression was evaluated in human gastric cancer cell lines SGC-7901 and MGC-803 by real time polymerase chain reaction (RT-PCR). Four segments of small interference RNA (siRNA) targeting CLIC1 mRNA and a no-sense control segment were designed by bioinformatics technology. CLIC1 siRNA was selected using Lipofectamine 2000 and transfected transiently into human gastric cancer SGC-7901 and MGC-803 cells. The transfected efficiency was observed under fluorescence microscope. After transfection, mRNA expression of CLIC1 was detected with RT-PCR and Western blotting was used to detect the protein expression. Proliferation was examined by methyl thiazolyl tetrazolium and apoptosis was detected with flow cytometry. Polycarbonate membrane transwell chamber and Matrigel were used for the detection of the changes of invasion and migration of the two cell lines.RESULTS: In gastric cancer cell lines SGC-7901 and MGC-803, CLIC1 was obviously expressed and CLIC1 siRNA could effectively suppress the expression of CLIC1 protein and mRNA. Proliferation of cells transfected with CLIC1 siRNA3 was enhanced notably, and the highest proliferation rate was 23.3% (P = 0.002) in SGC-7901 and 35.55% (P = 0.001) in MGC-803 cells at 48 h. The G2/M phase proportion increased, while G0/G1 and S phase proportions decreased. The apoptotic rate of the CLIC1 siRNA3 group obviously decreased in both SGC-7901 cells (62.24%, P = 0.000) and MGC-803 cells (52.67%, P = 0.004). Down-regulation of CLIC1 led to the inhibition of invasion and migration by 54.31% (P = 0.000) and 33.62% (P = 0.001) in SGC-7901 and 40.74% (P = 0.000) and 29.26% (P = 0.002) in MGC-803. However, there was no significant difference between the mock group cells and the negative control group cells.CONCLUSION: High CLIC1 expression can efficiently inhibit proliferation and enhance apoptosis, migration and invasion of gastric cancer cells in vitro. CLIC1 might be a promising target for the treatment of gastric cancer.     

Anticancer effects of sweet potato protein on human colorectal cancer cells

AIM: To investigate the effects of proteins purified from sweet potato storage roots on human colorectal cancer cell lines. METHODS: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Hoechst 33258 nuclear staining and Boyden transwell chamber methods were used to determine whether purified sweet potato protein (SPP) from fresh sweet potato roots affected proliferation, migration and invasion, respectively, of human colorectal cancer SW480 cells in vitro . The inhibitory effects of SPP on growth of human colorectal cancer HCT-8 cells intraperitoneally xenografted in nude mice and spontaneous lung metastasis of murine Lewis lung carcinoma 3LL cells subcutaneously transplanted in C57 BL/6 mice were also investigated in vivo . RESULTS: SPP inhibited the proliferation of SW480 cells in a dose-dependent manner, with an IC 50 value of 38.732 μmol/L (r2 = 0.980, P = 0.003) in the MTT assay. Hoechst 33258 nuclear staining further revealed inhibition of cell viability and induction of apoptosis by SPP. The transwell assay disclosed significant reduction in migrated cells/field by 8 μmol/L SPP (8.4 ± 2.6 vs 23.3 ± 5.4, P = 0.031) and invaded cells/field through the ECMatrix by 0.8 μmol/L SPP, compared with the control (25.2 ± 5.2 vs 34.8 ± 6.1, P = 0.038). Both intraperitoneal (ip) and intragastric (ig) administration of SPP led to significant suppression of growth of intraperitoneally inoculated HCT-8 cells in nude mice to 58.0% ± 5.9% (P = 0.037) and 43.5% ± 7.1% (P = 0.004) of the controls, respectively, after 9 d treatment. Bloody ascites additionally disappeared after ip injection of trypsin inhibitor. Notably, ig and ip administration of SPP induced a significant decrease in spontaneous pulmonary metastatic nodule formation in C57 BL/6 mice (21.0 ± 12.3 and 27.3 ± 12.7 nodules/lung vs 42.5 ± 4.5 nodules/lung in controls, respectively, P < 0.05) after 25 d treatment. Moreover, the average weight of primary tumor nodules in the hind leg of mice decreased from 8.2 ± 1.3 g/mice in     

Micro RNA-1290 promotes esophageal squamous cell carcinoma cell proliferation and metastasis

AIM:To investigate the biological role of mi R-1290 in esophageal squamous cell carcinoma(ESCC) progression and invasion and the underlying mechanism.METHODS:Quantitative real-time polymerase chain reaction(q RT-PCR) was performed to evaluate mi R-1290 expression in ESCC tissue samples.The roles of mi R-1290 in cell proliferation,migration and invasion were identified using mi R-1290 mimic-transfected cells.In addition,the regulatory effect of mi R-1290 on suppressor of cancer cell invasion(SCAI) was evaluated using q RT-PCR,Western blot analysis and a dual luciferase reporter assay.RESULTS:mi R-1290 was significantly upregulated in ESCC tissue samples compared with normal adjacent tissues(9.213 ± 1.150 vs 1.000 ± 0.0),(P 0.01).Upregulation of mi R-1290 was associated with tumor differentiation(P = 0.021),N classification(P = 0.006) and tumor-node-metastasis stage(P = 0.021) in ESCC patients.Moreover,ectopic mi R-1290 expression potently promoted ESCC cell growth(P 0.01),migration(P 0.01) and invasion(P 0.01) in vitro.mi R-1290 overexpression in ESCC cell lines decreased SCAI expression at the translational level and reduced SCAI-driven luciferase-reporter activity(P 0.01).CONCLUSION:Our findings suggested that mi R-1290 may play an oncogenic role in cellular processes of ESCC.     

Suppression of colorectal cancer metastasis by nigericin through inhibition of epithelial-mesenchymal transition

AIM: To evaluate the effect of nigericin on colorectal cancer and to explore its possible mechanism.METHODS: The human colorectal cancer (CRC) cell lines HT29 and SW480 were treated with nigericin or oxaliplatin under the conditions specified. Cell viability assay and invasion and metastasis assay were performed to evaluate the effect of nigericin on CRC cells. Sphere-forming assay and soft agar colony-forming assay were implemented to assess the action of nigericin on the cancer stem cell properties of CRC cells undergone epithelial-mesenchymal transition (EMT).RESULTS: Compared with oxaliplatin, nigericin showed more toxicity for the HT29 cell line (IC50, 12.92 ± 0.25 μmol vs 37.68 ± 0.34 μmol). A similar result was also obtained with the SW116 cell line (IC50, 15.86 ± 0.18 μmol vs 41.02 ± 0.23 μmol). A Boyden chamber assay indicated that a significant decrease in the number of HT29 cells migrating through polyvinylidene fluoride membrane was observed in the nigericin-treated group, relative to the vehicle-treated group [11 ± 2 cells per high-power field (HPF) vs 19.33 ± 1.52 cells per HPF, P < 0.05]. Compared to the control group, the numbers of HT29 cells invading through the Matrigel-coated membrane also decreased in the nigericin-treated group (6.66 ± 1.52 cells per HPF vs 14.66 ± 1.52 cells per HPF, P < 0.05). Nigericin also reduced the proportion of CD133⁺ cells from 83.57% to 63.93%, relative to the control group (P < 0.05). Nigericin decreased the number of spheres relative to the control group (0.14 ± 0.01 vs 0.35 ± 0.01, P < 0.05), while oxaliplatin increased the number of spheres relative to the control group (0.75 ± 0.02 vs 0.35 ± 0.01; P < 0.05). Nigericin also showed a decreased ability to form colonies under anchorage-independent conditions in a standard soft agar assay after 14 d in culture, relative to the control group (1.66 ± 0.57 vs 7 ± 1.15, P < 0.05), whereas the colony numbers were higher in the oxaliplatin group relative to the vehicle-treated controls (14.33 ± 0.57 vs 7 ± 1.15, P < 0.05). We further detected the expression of E-cadherin and vimentin in cells treated with nigericin and oxaliplatin. The results showed that HT29 cells treated with nigericin induced an increase in E-cadherin expression and a decrease in the vimentin expression relative to vehicle controls. In contrast, oxaliplatin downregulated the expression of E-cadherin and upregulated the expression of vimentin in HT29 cells relative to vehicle controls.CONCLUSION: This study demonstrated that nigericin could partly reverse the EMT process during cell invasion and metastasis.     

Dihydromyricetin inhibits migration and invasion of hepatoma cells through regulation of MMP-9 expression

AIM:To investigate the effects of dihydromyricetin(DHM)on the migration and invasion of human hepatic cancer cells.METHODS:The hepatoma cell lines SK-Hep-1 and MHCC97L were used in this study.The cells were cultured in RPIM-1640 medium supplemented with 10%fetal bovine serum at 37℃in a humidified 5%CO2incubator.DHM was dissolved in dimethyl sulfoxide and diluted to various concentrations in medium before applying to cells.MTT assays were performed to measure the viability of the cells after DHM treatment.Wound healing and Boyden transwell assays were used to assess cancer cell motility.The invasive capacity of cancer cells was measured using Matrigel-coated transwell chambers.Matrix metalloproteinase(MMP)-2/9 activity was examined by fluorescence analysis.Western blot was carried out to analyze the expression of MMP-2,MMP-9,p-38,JNK,ERK1/2 and PKC-δproteins.All data were analyzed by Student’s t tests in GraphPad prism 5.0software and are presented as mean±SD.RESULTS:DHM was found to strongly inhibit the migration of the hepatoma cell lines SK-Hep-1(without DHM,24 h:120±8μmol/L vs 100μmol/L DHM,24h:65±10μmol/L,P<0.001)and MHCC97L(without DHM,24 h:126±7μmol/L vs 100μmol/L DHM,24h:74±6μmol/L,P<0.001).The invasive capacity of the cells was reduced by DHM treatment(SK-Hep-1cells without DHM,24 h:67±4μmol/L vs 100μmol/L DHM,24 h:9±3μmol/L,P<0.001;MHCC97L cells without DHM,24 h:117±8μmol/L vs 100μmol/L DHM,24 h:45±2μmol/L,P<0.001).MMP2/9 activity was also inhibited by DHM exposure(SK-Hep-1 cells without DHM,24 h:600±26μmol/L vs 100μmol/L DHM,24 h:100±6μmol/L,P<0.001;MHCC97L cells without DHM,24 h:504±32μmol/L vs 100μmol/L DHM 24 h:156±10μmol/L,P<0.001).Western blot analysis showed that DHM decreased the expression level of MMP-9 but had little effect on MMP-2.Further investigation indicated that DHM markedly reduced the phosphorylation levels of p38,ERK1/2 and JNK in a concentration-dependent manner but had no impact on the total protein levels.In addition,PKC-δprotein,a key protein in the regulation of MMP family protein expression,was up-regulated with DHM treatment.CONCLUSION:These findings demonstrate that DHM inhibits the migration and invasion of hepatoma cells and may serve as a potential candidate agent for the prevention of HCC metastasis.     

大黄酸通过miR-29c-3p调节FSCN1的表达影响胃癌细胞的生物学行为

目的 探讨大黄酸(Rhein)对人胃癌细胞(SGC-7901)增殖、迁移、侵袭、凋亡的影响及其机制.方法 通过qRT-PCR检测大黄酸处理后细胞中miR-29c-3p的表达以及miR-29c-3p的转染效率;miR-29c-3p mimics组、NC mimics组、Rhein+miR-29c-3p inhibitor...